Manuals_files/CD Manual 12.pdf - Removable Prosthodontics

Maxillo-mandibular Relationships - 37
Protrusive Records
When a balanced occlusion is selected, a protrusive record should be made, in order to set
the condylar guidance.
1. The patient should be allowed to protrude a minimum of 5-6 mm (for ease of
determination) but less than 12 mm (maximum travel of the condylar element on the most
articulator).
2. Elastomeric registration material is placed over the entire mandibular rim and the patient
closes in an anterior position.
3. The registration media must interdigitate with the opposing "V-shaped" notches placed
previously.
4. The record is taken at a height greater than the established vertical dimension.
5. The record bases and registration are removed, placed on the articulator.
6. The condylar elements are released from the hinge position, the instrument protruded,
and the records approximated. The condylar elements are rotated until there is maximum
interdigitation of the registration and opposing occlusal rims.
7. ONLY the wax rims and registration should contact. If the casts and/or record bases
contact, eliminate the contacts and reseat into the record.
8. The lateral component of condylar guidance (Bennett Angle) can be set arbitrarily at
15°or the lateral component can be determined using the formula: L = (H/8) + 12
9. When a monoplane occlusion is selected, the protrusive record may be omitted.
However, it may be advantageous to alter the occlusal plane angle in patients with steep
condylar guidance, in order to improve denture stability. This cannot be assessed if the
condylar guidance has not been set on the articulator. If a protrusive record is not
obtained, the condylar guidance should be set at 0°.
References
1. Brill N, Schubeler S and Tryde G. Influence of occlusal patterns on movements of the mandible. J. Prosthet. Dent.
12:255, 1962.
2. Celenza F. The theory and clinical management of centric positions: II. Centric relation and centric relation
occlusion. Int. J. Periodont. and Rest. Dent., 4:63, 1984.
3. Crum RJ, Loiselle RJ. Oral perception and proprioception: a review of the literature and its significance to
prosthodontics. J. Prosthet. Dent. 28:215, 1972.
4. Grasser GN. An evaluation of terminal hinge position and neuromuscular position in edentulous patients. Part 1.
Maxillomandibular recordings. J. Prosthet. Dent. 36:491, 1976.
5. Reynolds JM. Occlusal wear facets. J. Prosthet. Dent. 24:367, 1970.
6. Wilson J, Nairn RI. Occlusal contacts in mandibular retrusion. Int J Prosthodont. 2:143, 1989.
7. Yurkstas A and Kapur K. Factors influencing centric relation records in edentulous mouths. J. Prosthet. Dent.
14:1054, 1964.